Presently, the tooth spacers (a.k.a. matrix bands) are a common tool used in dentistry. Matrix bands are used in dental practice to separate (isolate) restoring tooth having a proximal surface requiring restoration and an, intact proximal tooth not requiring restoration. In dentistry, teeth which are subject to decay are typically drilled or otherwise prepared by removing the decayed tooth material. This leaves an aperture, slot or other void in the tooth which is then filled with composite resin or other filling material. A Class 2 filling is a dental procedure in which a decayed area of a tooth along a portion of one or both proximal surfaces is prepared and filled. The proximal surfaces of a tooth are those surfaces of the tooth that face the surface of an adjacent tooth. The proximal surface that faces an adjacent tooth toward the front of the dental arch may be referred to as the mesial proximal surface. The proximal surface that faces an adjacent tooth toward the back of the dental arch may be referred to as the distal proximal surface.
When dentists perform Class 2 cavity preparations, they typically insert a temporary substrate adjacent to the cavity preparation to contain and shape the filling material. The temporary substrate that dentists have traditionally used is an elongated band called a matrix band. Mostly, the matrix band is of metallic material and is positioned around a tooth to be filled. The band is then tightened around the tooth, with a some kind of a clamping device, in order to form a mold or an appropriate support for applying a filling material to the tooth.
The matrix bands are a common and long-used dental implements and the problems do exist with the currently used technology. Also, the matrix bands of the most prior art are metallic.
For example, the matrix band by U.S. Pat. No. 6,749,429 a support base with a coating, at least one aperture (preferably two apertures may be centrally located in the width area of coated matrix band) used to assist in the removal of coated matrix band by a dental instrument, e.g. such as an explorer. More particularly, the matrix band comprises a stainless steel support base, the coating being based on either a tin alloy of 2 percent by weight gold and 98 percent by weight tin, being applied to a tooth under repair, or the tin alloy is replaced with an alloy of 2 percent by weight tin and 98 percent by weight indium, or the tin alloy is replaced with an alloy mixture of equal parts by weight of 2 percent by weight gold and 98 percent by weight tin and two percent by weight tin and 98 percent by weight indium.
Two diametrically opposed apertures are preferably presented in the matrix band of the diameter providing the explorer, fits in apertures and facilitates removal of the matrix band.
While these known matrix bands provide their functional purpose, they are complex considering the presence of the apertures and necessity to use additionally the dental instrument, e.g. such as explorer. Additionally, such matrix bands (surrounding the tooth) do not provide access to the cavity located in the lowest part of the outside portion of the tooth, and the sharp lowest edge can injure the gingiva (if spacer stays not exactly vertically /under the angle to the horizontal level/ or gum (if spacer stays exactly vertically to the horizontal level).
It is known, that before being placed in the patient's mouth, a matrix band usually is placed in a retaining device or other type of tool to position and tighten the band around the tooth so that it at least partially surrounds and conforms closely to the shape of the tooth.
When restoring a tooth, it is known and important to achieve a closed contact between the restored surface and the adjacent tooth to prevent food from becoming impacted between the teeth and causing periodontal disease. One problem with conventional matrix bands is that when they are removed from a Class 2 filling made with composite filling material, a gap often remains between the filled tooth and the adjacent tooth. The gap is typically roughly as wide as the thickness of the matrix band which was used in the filling. In order to solve the problem of open contacts in Class 2 composite fillings, dentists sometimes employ special techniques and tools to separate or otherwise force apart the adjacent teeth during the filling process. After the filling material is cured, the device separating the adjacent teeth is removed to permit the teeth to spring back together, hopefully just far enough to leave a fully closed contact between the teeth. One specific technique involves the use of mechanical separation driven in place by finger pressure between adjacent teeth at a location well below the contact area. Another known technique involves forcefully separating the teeth by use of a metal ring which applies powerful forces inward between the teeth at a location just beneath where they meet.
Sometimes, such forceful separation of adjacent teeth may be difficult for the dentist and uncomfortable for the patient. Another disadvantage of using techniques involving forceful separation of adjacent teeth is that the extent to which the teeth will spring back together following the procedure is somewhat unpredictable. Moreover, in a Class 2 filling in which a matrix band is positioned around a tooth having a prepared proximal surface (i.e., a proximal surface requiring restoration) and an intact proximal surface (i.e., a proximal surface not requiring restoration), the thickness of the band between the intact proximal surface and an adjacent tooth tends to push, or drive, the tooth being filled toward the tooth adjacent the prepared surface. Consequently, additional force is required to adequately separate apart the adjacent teeth on the side of the prepared surface for packing the filling material into the cavity.
As well known in the dental practice, the attempts to solve the problem of open contacts that requires less forceful separation of adjacent teeth are to use matrix bands having areas of reduced thickness for insertion between the proximal surfaces of adjacent teeth. However, if a tooth has only one prepared proximal surface, matrix bands of this type can be difficult to place between the tight intact interproximal contact (i.e., the contact between the intact proximal surface not requiring restoration and an adjacent tooth) because the band is very thin and pliable. Such a band may buckle or tear and may not slide through the intact interproximal contact. Shorter matrix bands provide a form to enclose the proximal surface requiring restoration but are not long enough to completely encircle the tooth, and therefore do not require insertion between the intact interproximal contact. One popular version of a shorter band is known as a sectional matrix. However, such short matrix bands are undesirable in that they are difficult to tighten around a tooth and maintain a close contact between the inner surface of the band and the outer contour of the prepared tooth to avoid the formation of a ledge at the gingival edge of the filling.
Therefore, the dental insert (matrix band) by U.S. Pat. No. 6,736,639 is represented by an elongated band having first and second spaced apart central portions. According to this aspect of the disclosure, a tooth insert is provided for engaging around a first tooth having a prepared proximal surface requiring restoration adjacent to a second tooth and an intact proximal surface adjacent to a third tooth at the opposite side of the first tooth from the second tooth. The described in this invention matrix band comprises a gingival edge and an occlusal edge which is opposed to and spaced from the gingival side, a pair of opposite transversely spaced side edges extending between the respective gingival and occlusal edges. The “gingival edge” refers to the edge of the body which is positioned closest to the patients gum when the band is inserted in place. Also the band comprises an elongated body having first and second elongated leg portions that join together at a central region. The body is of the inverted v-shaped configuration with the apex of the configuration being positioned at the central region, and has two spaced apart central portions, each of which is positioned in a respective one of the elongated leg portions. The central portions are desirably located on the body so that they are positioned at least in part proximal surfaces of adjacent teeth. Thus, the first central portion is positioned between the adjacent surfaces of teeth and while the another central portion is positioned between the adjacent surfaces of teeth.
The restoring tooth is located on the mesial side of tooth, and the adjacent tooth is located on the distal side of tooth. The restoring tooth has a prepared cavity on its distal proximal surface. The mesial proximal surface of tooth is intact and does not require restoration. The adjacent teeth have interproximal contact areas where the teeth are closest to or in contact with one another. Thus, a distal interproximal contact is formed between the distal proximal surface of tooth and the mesial proximal surface of the adjacent tooth. The cavity preparation has completely eliminated the interproximal contact between teeth. A mesial interproximal contact is formed between the mesial proximal surface of the restoring tooth and the distal proximal surface of it. The leg portion of the band contains a centrally located aperture positioned in central portion to permit at least partial interproximal contact between the intact proximal surface of teeth: The aperture minimizes separation of teeth. Aperture is oval in shape, with the major axis of the aperture extending generally lengthwise of the band, and is dimensioned to be larger than the area occupied by the intact interproximal contact, such as larger than the contact area of the teeth to maintain the full interproximal contact therebetween and to eliminate separation caused by the thickness of the band when the band is positioned around a tooth.
When the band is in place around a tooth for filling, the band does not cause that tooth to move toward a tooth adjacent to the prepared cavity. As a result, additional separation of the restoring tooth with the prepared proximal surface and an adjacent tooth is not required to result in an acceptably tight finished interproximal contact. The aperture must not be so large as to overly weaken leg portion. Leg portion is rigid to withstand the pressure needed to push it down through the intact interproximal contact without tearing or buckling. The aperture is spaced from the gingival edge and the occlusal edge of leg portion so that a peripheral or reinforcing region of the body bounds aperture. Such a construction enhances the rigidity of leg portion 6 to facilitate the insertion of leg down through the intact interproximal without the leg 6 tearing or buckling. The outline of the body may be extended in the occlusal direction to form a projection (lip) over the aperture. The projection adds rigidity to leg portion around aperture and also provides a convenient location on which a dentist can apply finger pressure in order to push the gingival edge of leg portion down through the intact interproximal contact area between teeth.
This matrix band has the same deficiencies, i.e. it is complex considering the presence of the apertures, and such matrix bands (surrounding the tooth) do not provide convenient access to the cavity located in the lowest part of the outside portion of the restoring tooth. Additionally, the sharp lowest edge can injure the gingiva (if spacer stays not exactly vertically /under the angle to the horizontal level/) or gum (if spacer stays exactly vertically to the horizontal level).
As have been described above the matrix bands are commonly used to confine the placement of a Class 2 dental restoration and to provide anatomical form to the restoration for proper proximal contact of posterior teeth, and, as have been mentioned, the matrix bands traditionally completely encircle the tooth and remain stable and inflexible during placement of the restorative material, providing the restoration with a smooth surface and assuring that properly condensed or injected restorative material will not escape the confines of the band, causing excess at cavosurface margins. A screw-tightened, mechanically-retained matrix band system is widely used. The problem with custom-contoured matrix bands is that they require a great deal of operating time. The use of individual matrix segments hand-cut from a long strip of suitable material which are then custom-shaped by the dentist during the restoration procedure is known, however, this process is also time-consuming and achieving intricate shapes of the matrix strips is not possible using dental hand cutting tools.
Therefore, the matrix band segment by U.S. Pat. No. 5,425,635 is a portion of matrix material sufficient to cover the interproximal area of the restoration which is shaped for easy application and removal. According to the procedure disclosed herein, the matrix segment is shaped to the tooth contour, applied interproximally between the teeth. The segment is then can be removed in the occlusal direction. Occlusal matrix removal can fracture setting amalgam. Application and removal of the segment is accomplished by use of pliers; or optionally, the segment may be removed by means of attaching and pulling it away with a string-like material such as dental floss or thicker dental tape.
The matrix band segment comprises a top and a bottom portions with opposing left and right sides. The top portion is wider than the bottom portion, and to prevent laceration of the gingival tissues, the sides have smooth tapered edges. The sides converge in the direction of the bottom portion. The top portion includes plier-gripping ears that facilitate the placement and removal of the segment. One or both of the ears may include an aperture for the optional application of a removal string. The segment is first contoured with contouring pliers well-known in the dental arts to replicate the original proximal anatomical form. The contoured segment is applied between teeth and slightly bent around the restoring tooth. The matrix segment is now in place for the application and condensation of restorative material. The matrix segment is then removed. To assist in removing the string is applied through an aperture in one ear of the segment, and the segment laterally removed by pulling the string. The string also serves as a safety tether, preventing the segment from inadvertent displacement during the dental procedure.
This matrix band is complex considering the presence of the apertures and the string, preventing the segment from inadvertent displacement during the dental procedure. Also, the sharp lowest edge can injure the gingiva (if spacer stays not exactly vertically /under the angle to the horizontal level/ or gum (if spacer stays exactly vertically to the horizontal level).
Usually, the known conventional matrix bands have been at least ten microns in thickness and separate the teeth apart slightly. This separation has not been a problem when used with amalgam filling material packed between two adjacent teeth. However, new aesthetically pleasing and structurally strong materials have been developed such as composite resin materials. The new composite resin materials is that they cannot be packed as easily into a tooth cavity as amalgam. Also, the thick tooth spacers (matrix bands, strips, etc.) have been used to accomplish this desired separation. As a result, following filling and when the strips are removed, a small space or gap is left between the teeth. Any such gap or interproximal space, even when very small, is a trap for food to lodge between the teeth during chewing. This as was mentioned above contributes to tooth cavities and gum diseases, such as periodontal disease.
Additionally, composite resins have been bonded to the teeth for the purpose of correcting the bite of a patient. The composite resin may be applied to the upper surface of several teeth simultaneously and the mouth then closed in the desired therapeutic jaw position to establish the proper bite. With this approach, it is difficult to prevent the composite resin from ending up in the interproximal space between the teeth and it is also difficult to remove this resin from this space once it is there. If conventional interproximal strips are used between the teeth, they push adjacent teeth apart and thereby slightly change the positions of the teeth. When these strips are removed following the resin bonding treatment, the teeth return to their original positions, which makes the bite no longer as accurate as desired.
Therefore, Summer describes a matrix band (tooth spacer) in his U.S. Pat. No. 5,505,618. The tooth spacer is inserted between interproximal surfaces of a tooth to be treated, and an adjacent tooth. The tooth spacer comprises an elongated body having a pair of opposite transversely spaced sidewalls or edges, and a gingival edge and an occlusal edge (the term “gingival edge” refers to the edge of the body positioned closest to the patient's gum when the spacer is inserted in place). The elongated body has a recessed or thin central portion at least partially surrounded or enclosed by a peripheral portion. Also, the spacer may be bent to conform to the tooth shape during insertion. The spacer also includes the thin central portion and the thick portion.
The thin central portion is of a material that is sufficiently rigid to withstand being forced down between the adjacent teeth at a contact area. The thin central portion extends from the gingival edge to a location adjacent the occlusal edge. The thinned central portion is dimensioned to be larger than the contact area, and the central portion is extended all the way to the occlusal edge. However, it is preferred to have a thicker reinforcing portion of the tooth spacer bounding the central portion. The thin central portion is made by either a grinding, molding, casting, chemical etching, stamping or any other process suitable for achieving a recessed or thinned area. The height or distance the central portion extends from the gingival edge is from seventy-five to ninety-five percent of the overall height of the tooth spacer. The peripheral portion has a thickness greater than the thickness of the central portion to provide reinforcement and rigidity to the tooth spacer. Also, the peripheral portion extends between the central portion and the respective side walls and between the central portion and the occlusal edge. A reinforcing portion may is positioned along the gingival edge of the tooth spacer as this edge ends up in the gap below the contacting areas of the teeth after the tooth spacer has been inserted.
This spacer does not provide the sufficient contact of the spacer (matrix band) to the lower portion of the teeth (the distance between teeth at their lower portion is significantly bigger than the distance between teeth at their upper portion), and the spacer's position is not secure, that can cause an inadvertent displacement of the spacer during the dental procedure. Additionally, the known spacer is complex considering its multi-thickness, and the sharp lowest edge can injure the gingiva (if spacer stays not exactly vertically /under the angle to the horizontal level/ or gum (if spacer stays exactly vertically to the horizontal level).
Thus, there is a great need in the art for the improved not complex, not expensive and non-obstructive matrix band that is easily formed, placed, and removed, and that provides the convenience during dental procedure.